Vulnerable Plaques In Coronary Arteries Research Articles

Abstract 18637: Lower α-Klotho is Associated With Vulnerable Coronary Artery Plaque Characteristics

Introduction: α-Klotho (klotho) is a geroprotective protein inversely associated with coronary artery disease CAD and vascular aging. This study used intravascular ultrasound (IVUS) to study coronary artery plaque characteristics of patients with low circulating klotho. Hypothesis: Lower klotho is associated with vulnerable coronary artery plaque characteristics. Methods: Patients undergoing coronary angiogram for chest pain who had no CAD (<40% stenosis) underwent IVUS assessment. Images were obtained from the mid-LAD to the coronary ostium. Stored arterial plasma was used for α-klotho analysis by enzyme-linked immunosorbent assay. Results: A total of 58 consecutive patients were retrospectively studied. The median circulating klotho level of the cohort was 0.27 ng/mL [0.15; 1.24]. Patients with klotho less than the median were compared to those with levels greater than or equal to the median and were similar in age (53 ±11 vs. 56 ±10, p = 0.235) and sex distribution (86% vs. 76% female, p = 0.324). Patients with less klotho had higher coronary plaque burden (21.42% [17.185, 31.955] vs. 18.32 [10.5, 24.515], p=0.041) and larger plaque area (2.71 [2.03, 4.605] vs . 2.27 [1.41, 3.31] mm 3 /mm, p=0.058) compared to those with higher klotho. Lower klotho was associated with vulnerable plaque characteristics, including greater percentages of dense calcium (1.33% [0.265, 5.38] vs. 0.43% [0.015, 1.73], p=0.037) and necrotic core (5.43% [2.245, 10.5] vs. 2.22% [0.86, 4.50], p=0.011). Conclusions: Lower circulating klotho was associated with higher coronary plaque burden and vulnerable plaque characteristics. Klotho may be an early biomarker for risk in coronary artery disease.

Testing the Effects of App-Based Motivational Messages on Physical Activity and Resting Heart Rate Through Smartphone App Compliance in Patients With Vulnerable Coronary Artery Plaques: Protocol for a Microrandomized Trial.

Achieving the weekly physical activity recommendations of at least 150-300 minutes of moderate-intensity or 75-150 minutes of vigorous-intensity aerobic exercise is important for reducing cardiometabolic risk, but evidence shows that most people struggle to meet these goals, particularly in the mid to long term. The Messages Improving Resting Heart Health (MIRTH) study aims to determine if (1) sending daily motivational messages through a research app is effective in improving motivation and in promoting adherence to physical activity recommendations in men and women with coronary heart disease randomized to a 12-month intensive lifestyle intervention, and (2) the time of the day when the message is delivered impacts compliance with exercise training. We will conduct a single-center, microrandomized trial. Participants will be randomized daily to either receive or not receive motivational messages over two 90-day periods at the beginning (phase 1: months 4-6) and at the end (phase 2: months 10-12) of the Lifestyle Vulnerable Plaque Study. Wrist-worn devices (Fitbit Inspire 2) and Bluetooth pairing with smartphones will be used to passively collect data for proximal (ie, physical activity duration, steps walked, and heart rate within 180 minutes of receiving messages) and distal (ie, change values for resting heart rate and total steps walked within and across both phases 1 and 2 of the trial) outcomes. Participants will be recruited from a large academic cardiology office practice (Central Sydney Cardiology) and the Royal Prince Alfred Hospital Departments of Cardiology and Radiology. All clinical investigations will be undertaken at the Charles Perkins Centre Royal Prince Alfred clinic. Individuals aged 18-80 years (n=58) with stable coronary heart disease who have low attenuation plaques based on a coronary computed tomography angiography within the past 3 months and have been randomized to an intensive lifestyle intervention program will be included in MIRTH. The Lifestyle Vulnerable Plaque Study was funded in 2020 and started enrolling participants in February 2022. Recruitment for MIRTH commenced in November 2022. As of September 2023, 2 participants were enrolled in the MIRTH study and provided baseline data. This MIRTH microrandomized trial will represent the single most detailed and integrated analysis of the effects of a comprehensive lifestyle intervention delivered through a customized mobile health app on smart devices on time-based motivational messaging for patients with coronary heart disease. This study will also help inform future studies optimizing for just-in-time adaptive interventions. Australian New Zealand Clinical Trials Registry ACTRN12622000731796; https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=382861. DERR1-10.2196/46082.

Roadmap on the use of artificial intelligence for imaging of vulnerable atherosclerotic plaque in coronary arteries.

Artificial intelligence (AI) is likely to revolutionize the way medical images are analysed and has the potential to improve the identification andanalysis of vulnerable or high-risk atherosclerotic plaques in coronary arteries, leading to advances in the treatment of coronary artery disease. However, coronary plaque analysis is challenging owing to cardiac and respiratory motion, as well as the small size of cardiovascular structures. Moreover, the analysis of coronary imaging data is time-consuming, can be performed only by clinicians with dedicated cardiovascular imaging training, and is subject to considerable interreader and intrareader variability. AI has the potential to improve the assessment of images of vulnerable plaque in coronary arteries, but requires robust development, testing and validation. Combining human expertise with AI might facilitate the reliable and valid interpretation of images obtained using CT, MRI, PET, intravascular ultrasonography and optical coherence tomography. In this Roadmap, we review existing evidence on the application of AI to the imaging of vulnerable plaque in coronary arteries and provide consensus recommendations developed by an interdisciplinary group of experts on AI and non-invasive and invasive coronary imaging. We also outline future requirements of AI technology to address bias, uncertainty, explainability and generalizability, which are all essential for the acceptance of AI and its clinical utility in handling the anticipated growing volume of coronary imaging procedures.

Potential of optical coherence tomography and intravascular ultrasound in the detection of vulnerable plaques in coronary arteries

Intravascular imaging of vulnerable plaques in vivo has great potential for predicting coronary events. Currently, there are several methods of intravascular imaging, which make it possible to verify the components of the plaque and, accordingly, its vulnerability. The most common are virtual-histology intravascular ultrasound and optical coherence tomography. Several studies have shown that these imaging techniques can stratify the risk of adverse cardiovascular events, as well as assess the effectiveness of drug therapy. This article will describe the advantages and disadvantages of intravascular ultrasound and optical coherence tomography in identifying vulnerable coronary lesions.

Polymorphisms in F2, F7, and PAI1 genes in men with coronary atherosclerosis

Aim. To study the associations of polymorphisms in F2, F7, and PAI1 genes with the presence of vulnerable plaque in coronary arteries (CA) and the blood concentration of proteins encoded by these genes.Material and methods. The study included 101 men 40-70 years old with documented coronary atherosclerosis, who underwent coronary artery bypass grafting. According to the histological analysis of atherosclerotic plaques, men were divided into 2 groups: 40 men (39,6%) with stable plaque; 61 men (60,4%) with vulnerable plaques in CA. Genotyping of rs1799963 and rs6046 was performed by reverse transcription polymerase chain reaction, rs1799889 — by polymerase chain reaction. Statistical processing was performed using the SPSS 16.0 software package.Results. In patients with stable plaques, allele A of rs6046 polymorphism in the F7 gene was observed in 2,9 times more often (95% confidence interval (CI), 1,20-7,20, p=0,021) than in men with vulnerable plaques. The odds ratio of the GA genotype carriage is 4,03 times higher among patients with stable plaques in CA compared with vulnerable plaques (95% CI, 1,49-10,93, p=0,006). The odds ratio of the 5G/4G genotype carriage among patients with stable plaques in CA is 2,47 times higher than in patients with vulnerable plaques (95% CI, 1,08-5,62, p=0,039). The 4G/4G genotype carriage is 5,85 times much more common in men with stable plaques (95% CI, 1,61-21,34, p=0,003).Conclusion. Polymorphism in the PAI1 (rs1799889) and F7 (rs6046) genes are associated with the presence of vulnerable plaques in CA in men with verified coronary atherosclerosis. There were no differences between the groups in the frequencies of genotypes and alleles of the rs1799963 polymorphism of the F2 gene. Also, no significant differences were found in the blood levels of PAI-1 and factor VII in groups with different genotypes.

The association between statin pre-treatment and LDL Levels on the rate of STEMI presentation: data from the ACS Israeli Survey (ACSIS) 2008–2018

Abstract Background ST-elevation myocardial infarction (STEMI) mostly occurs as a result of vulnerable coronary artery plaque rupture. Constituting hypolipidemic and pleiotropic effects, statins stabilize coronary artery plaque and may prevent STEMI events. Purpose To determine the association between statin pre-treatment and its intensity, low-density-lipoprotein cholesterol (LDL-C) levels and presentation of patients with an ACS (STEMI vs. NSTEMI/unstable angina [UAP]). Methods Data was drawn from the Acute Coronary Syndrome Israeli Survey (ACSIS), a biennial prospective survey of ACS patients hospitalized in all CCU/Cardiology departments during 2008–2018. The rate of STEMI vs NSTEMI/UAP at the time of presentation was calculated by LDL-C levels on admission, stratified to 5 subgroups (<50, 50–69, 70–100, 101–130 and >130 mg/dl) and the use of statins, including statin intensity prior to the index ACS event. Results Among 5,103 patients, 875 (17%) were pre-treated with high intensity statin (HIST), 1,389 (27%) with low intensity statin (LIST), and 2,839 (56%) were statin naive patients. Statin-pre-treated patients were older, more likely to suffer from co-morbidities and cardiovascular diseases and were more often pre-treated with anti-platelets. The proportion of patients presenting with STEMI vs. NSTEMI/UAP was significantly lower among HIST vs. LIST vs. statin naive patients (31.0%, 37.8%, 54.0%, respectively, p for trend <0.001). At each LDL-C level, the proportion of STEMI was significantly lower among HIST vs. LIST vs. statin naive patients. Multivariate analysis adjusting for pertinent variables including propensity score for statin use, revealed that HIST was independently associated with lower STEMI presentation, but LDL-C<70 and LIST were not. Conclusions Among patients admitted with ACS, pre-treatment with high intensity statin but not LDL-C level, was independently associated with a lower probability of presenting with STEMI. Funding Acknowledgement Type of funding source: None

The randomized study of preventive revascularization of vulnerable coronary artery plaques in patients with stable coronary artery disease

Background. Today, a number of unresolved issues remain regarding vulnerable coronary plaques, one of which is the need for preventive revascularization.Aim. Evaluation of the appropriateness of preventive revascularization of functionally insignificant lesions of the coronary arteries with signs of vulnerability according to the virtual histology of intravascular ultrasound in patients with stable coronary artery disease.Methods. The prospective randomized study includes patients with stable coronary artery disease and isolated intermediate-grade coronary stenosis. The first step in patients is measured fractional flow reserve to confirm the hemodynamic insignificance of stenosis. Then an intravascular ultrasound is performed to verify signs of plaque vulnerability: a thin-cap fibroatheroma and / or minimum lumen area <4 mm2 and/or plaque burden >70%. After that, patients are randomized into two groups: preventive revascularization or optimal medical therapy. After 12 months, patients undergo repeated intravascular ultrasound and end-point analysis.Results. So far, 10 patients have been included in the study (6 in the preventive revascularization group and 4 in the optimal medical therapy group). No endpoints and complications were recorded in both groups in 30-days follow-up.Conclusion. Intravascular imaging methods can identify vulnerable coronary plaques, which allows you to use a personalized approach in determining treatment tactics, one of which can be preventive revascularization.

An Innovative Method for Endovascular Stabilization of Vulnerable Plaque in Coronary Arteries: An Opinion

Despite all of the available diagnostic and treatment modalities atherosclerosis remains one of the most common healthcare problems worldwide with an estimated annual mortality rate of approximately 17,5 million cases

PET imaging of vulnerable coronary artery plaques

In the last years, the identification of vulnerable atherosclerotic plaques to prevent acute coronary events has been one of the main objectives of the cardiovascular science community. In this review, we provide an overview of vulnerable coronary artery plaque imaging by positron emission tomography (PET). Relevant methodological and technical aspects of PET on coronary artery plaque imaging are first analysed. Second, the main radiotracers used in this area as well as the main results of the clinical studies published so far are described. From published data, specialized approaches are recommended for imaging protocol and quantitative analysis of plaque activity. 18F-fluorodeoxyglucose (18F-FDG), the first radiotracer used for its wide availability, has several limitations for the detection and quantification of coronary artery plaque inflammation. 18F-sodium fluoride (18F-NaF), a marker of vascular microcalcification, seems to be the most promising radiotracer for vulnerable coronary artery plaque imaging. 68Ga-DOTATATE and 68Ga-pentixafor have also shown interesting results on coronary plaque inflammation in humans. Data on coronary imaging in humans are lacking for other radiotracers that target inflammation, hypoxia and neoangiogenesis. Molecular imaging by PET is a powerful tool for imaging different components of vulnerable coronary artery plaques and, potentially, for selecting patients at high-risk of myocardial infarction for personalized treatments. However, the results of large clinical trials on asymptomatic patients to link coronary plaque activity to patient outcome are strongly required.

The natural history of napkin-ring sign by coronary computed tomography angiography.

IntroductionDespite their significance, the prevalence and the incidence of vulnerable plaques in coronary arteries, as well as their natural history, remain poorly known.AimTo evaluate the prevalence, incidence and evolution of napkin-ring sign (NRS), and to establish factors associated with its presence, progression, or regression, in patients with suspected coronary artery disease (CAD).Material and methodsThe study is based on a single-center prospective registry. Eighty-nine patients with suspected CAD underwent two computed tomography angiography (CTA) examinations within an interval of at least 24 months. High-risk plaque was defined by the presence of a low-attenuation area adjacent to the coronary lumen, surrounded by a ring of higher attenuation – NRS.ResultsAt the baseline 53 NRS were observed in 22 (25%) patients, 7 (8%) patients had single NRS and 15 (17%) had multiple NRS. After the follow-up period, there were 68 NRS in 32 patients. In 18 patients progression was observed with 23 additional NRS. Presence of single NRS and diabetes were independent predictors of NRS progression.ConclusionsThe number of NRS plaque tends to increase over time in patients with suspected CAD. The progression may be predicted by the presence of diabetes or single NRS.

Therapeutic effects of different Atorvastatin doses on vulnerable plaques in coronary arteries assessed by intracoronary optical coherence tomography.

The aim of this study was to evaluate optical coherence tomography (OCT) as an assessment of the efficacy of atorvastatin treatment.Twenty-four acute coronary syndrome (ACS) patients were allocated to conventional-dose (20 mg atorvastatin, n = 12) and intensive-dose (40–80 mg atorvastatin, n = 12) groups and correlations between changes in the OCT measurements and blood routine indexes were analyzed 9 months post-percutaneous coronary intervention (PCI).Treatment with atorvastatin resulted in a significant increase in the target thin cap fibroatheroma (TCFA) fibrous cap thicknesses in both groups. The increase was bigger in the intensive-dose group than in the conventional-dose group (184.1 ± 57.4 μm vs. 125.1 ± 28.6, P = .005). The TCFA lipid core arc in both groups was significantly decreased compared with baseline (72.9 ± 29.3 vs. 127.6 ± 50.8, P < .01 and 74.6 ± 32.9 vs. 132.6 ± 51.3, P < .01, respectively). Correlation analyses showed an inverse relationship between low-density lipoprotein cholesterol (LDL-c) levels and the TCFA cap thickness, and a direct relationship between C-reactive protein (CRP) level and lipid core arc.Statins significantly increased the TCFA fibrous cap thickness and reduced the lipid core arc, and OCT measurements accurately reflected the levels of blood LDL-c and CRP.Trial registration: (Chinese Clinical Trial Registry) ChiCTR-IPR-17010874

A Dual-Modality Hybrid Imaging System Harnesses Radioluminescence and Sound to Reveal Molecular Pathology of Atherosclerotic Plaques

Atherosclerosis is a progressive inflammatory condition caused by an unstable lesion, called thin-cap fibro atheromata (TCFA) that underlies coronary artery disease (CAD)—one of the leading causes of death worldwide. Therefore, early clinical diagnosis and effective risk stratification is important for CAD management as well as preventing progression to catastrophic events. However, early detection could be difficult due to their small size, motion, obscuring 18F-FDG uptake by adjacent myocardium, and complex morphological/biological features. To overcome these limitations, we developed a catheter-based Circumferential-Intravascular-Radioluminescence-Photoacoustic-Imaging (CIRPI) system that can detect vulnerable plaques in coronary arteries and characterizes them with respect to pathology and biology. Our CIRPI system combined two imaging modalities: Circumferential Radioluminescence Imaging (CRI) and PhotoAcoustic Tomography (PAT) within a novel optical probe. The probe’s CaF2:Eu based scintillating imaging window provides a 360° view of human (n = 7) and murine carotid (n = 10) arterial plaques by converting β-particles into visible photons during 18F-FDG decay. A 60× and 63× higher radioluminescent signals were detected from the human and murine plaque inflammations, respectively, compared to the control. The system’s photoacoustic imaging provided a comprehensive analysis of the plaque compositions and its morphologic information. These results were further verified with IVIS-200, immunohistochemical analysis, and autoradiography.

Comparison of the Effect of Rosuvastatin 2.5 mg vs 20 mg on Coronary Plaque Determined by Angioscopy and Intravascular Ultrasound in Japanese With Stable Angina Pectoris (from the Aggressive Lipid-Lowering Treatment Approach Using Intensive Rosuvastatin for Vulnerable Coronary Artery Plaque [ALTAIR] Randomized Trial)

Diminishing yellow color, evaluated by coronary angioscopy, is associated with plaque stabilization and regression. Our aim was to assess the effect of aggressive lipid-lowering therapy with rosuvastatin on plaque regression and instability. Thirty-seven patients with stable angina or silent myocardial ischemia who planned to undergo elective percutaneous coronary intervention and had angioscopic yellow plaques of grade 2 or more were randomized to high-dose (group H, 20 mg/day, n = 18) or low-dose (group L, 2.5 mg/day, n = 19) rosuvastatin therapy for 48 weeks. Yellow plaque was graded on a 4-point scale of 0 (white) to 3 (bright yellow) by angioscopy, and plaque volume was determined by intravascular ultrasound for plaques with a length of 5 to 15 mm. Color and volume were assessed at baseline and after 48 weeks by the investigators blinded to the rosuvastatin dosage, and were compared between the 2 dosing groups. The level of low-density lipoprotein-cholesterol decreased from 130.3 ± 25.5 mg/dl to 61.7 ± 16.5 mg/dl (-50 ± 19%: high intensity) in group H (p <0.001) and from 130.9 ± 28.5 mg/dl to 89.7 ± 29.0 mg/dl (-30 ± 22%: moderate intensity) in group L (mean ± SD, p <0.001). The average color grade of yellow plaques decreased from 2.0 to 1.5 in group H (p <0.001) and from 2.0 to 1.6 in group L (p <0.001) after 48 weeks. Plaque volume decreased significantly in group H but not in group L. The percent change in plaque volume was significantly larger in group H than in group L (p = 0.005). In conclusion, both high-dose and low-dose rosuvastatin increased plaque stability. However, high-dose rosuvastatin was more effective than low-dose rosuvastatin in inducing plaque volume regression. Clinical Trial Registration No: UMIN-CTR, UMIN000003276.

Molecular imaging of plaques in coronary arteries with PET and SPECT.

Coronary artery disease remains a major cause of mortality. Presence of atherosclerotic plaques in the coronary artery is responsible for lumen stenosis which is often used as an indicator for determining the severity of coronary artery disease. However, the degree of coronary lumen stenosis is not often related to compromising myocardial blood flow, as most of the cardiac events that are caused by atherosclerotic plaques are the result of vulnerable plaques which are prone to rupture. Thus, identification of vulnerable plaques in coronary arteries has become increasingly important to assist identify patients with high cardiovascular risks. Molecular imaging with use of positron emission tomography (PET) and single photon emission computed tomography (SPECT) has fulfilled this goal by providing functional information about plaque activity which enables accurate assessment of plaque stability. This review article provides an overview of diagnostic applications of molecular imaging techniques in the detection of plaques in coronary arteries with PET and SPECT. New radiopharmaceuticals used in the molecular imaging of coronary plaques and diagnostic applications of integrated PET/CT and PET/MRI in coronary plaques are also discussed.

The culprit lesion score on multi-detector computed tomography can detect vulnerable coronary artery plaque

Vulnerable plaques are characterized by large lipid cores, positive remodeling and small coronary calcium deposits. Multi-detector computed tomography (MDCT) has recently been shown to be able to characterize coronary artery plaques. The aim of this study was to evaluate culprit coronary lesions for differentiating acute coronary syndrome (ACS) from stable angina pectoris (SAP) using MDCT. 64-slice MDCT was conducted on 71 patients (ACS: 35, SAP: 36). The culprit coronary lesions were assessed according to the type and plaque attenuation (PA) of the plaque and the remodeling index (RI) as the ratio of the lesion and the reference area. The culprit lesion score (CLS) was defined as the sum of every score as 1.2 for a PA≤60 Hounsfield units (HU), 1.1 for a RI≥1.05 and 1.2 for a non-calcified or spotty calcification. More spotty calcification (95.0% vs. 23.1%, P<0.001), a lower PA (40.17±20.08 HU vs. 96.96±58.19 HU, respectively, P<0.001) and a higher RI (1.44±0.43 vs. 0.90±0.44, respectively, P<0.001) were observed in the ACS patients. Also, the CLS of the ACS patients was significantly higher than that of the SAP patients (3.07±0.63 vs. 1.18±1.12, respectively, P<0.001). A CLS more than 2.0 helped us to differentiate ACS from SAP with a sensitivity of 97.1% and a specificity of 67.6%. The CLS might be a useful tool for differentiating ACS from SAP.

Fusing in-vitro and in-vivo intravascular ultrasound data for plaque characterization

Accurate detection of in-vivo vulnerable plaque in coronary arteries is still an open problem. Recent studies show that it is highly related to tissue structure and composition. Intravascular Ultrasound (IVUS) is a powerful imaging technique that gives a detailed cross-sectional image of the vessel, allowing to explore arteries morphology. IVUS data validation is usually performed by comparing post-mortem (in-vitro) IVUS data and corresponding histological analysis of the tissue. The main drawback of this method is the few number of available case studies and validated data due to the complex procedure of histological analysis of the tissue. On the other hand, IVUS data from in-vivo cases is easy to obtain but it can not be histologically validated. In this work, we propose to enhance the in-vitro training data set by selectively including examples from in-vivo plaques. For this purpose, a Sequential Floating Forward Selection method is reformulated in the context of plaque characterization. The enhanced classifier performance is validated on in-vitro data set, yielding an overall accuracy of 91.59% in discriminating among fibrotic, lipidic and calcified plaques, while reducing the gap between in-vivo and in-vitro data analysis. Experimental results suggest that the obtained classifier could be properly applied on in-vivo plaque characterization and also demonstrate that the common hypothesis of assuming the difference between in-vivo and in-vitro as negligible is incorrect.

Presence of vulnerable coronary plaques in middle-aged individuals who suffered a brain death

Vulnerable plaques in coronary arteries are frequently found in individuals who died suddenly or due to an acute coronary syndrome. The prevalence and characteristics of these plaques in the middle-aged apparently healthy population are unknown. From a total of 652 hearts from transplant donors collected between 1996 and 2007, we selected those from apparently healthy individuals older than 40 years old who died of head trauma or stroke and had no evidence of prior vascular diseases. The coronary arteries were examined by serial sectioning at 3 mm intervals, and all areas of cross-sectional luminal narrowing were processed for histological, immunohistochemical, and morphometric studies. The atherosclerotic plaques were classified according to the American Heart Association Report. A total of 160 hearts were examined. Mean age was 50.3 +/- 5.8 years. Sixty-eight hearts had no advanced coronary atherosclerotic lesions (Type I, II, and III of the American Heart classification). In the remaining 92 hearts, we found 179 plaques considered high-risk lesions (American Heart Association Type IV, V, and VI). These plaques were more frequently found in males (P < 0.001) and in those with a higher heart weight (P < 0.001). The median (25th and 75th percentiles) vascular narrowing value using a planimetric analysis was 32% (21-53). No significant association with the cause of death was found (P = 0.09). High-risk coronary artery plaques not associated with significant vascular lumen reduction exist in 57% of patients who suffered a brain death with a mean of 1.11 lesions prone to rupture per individual.

Proteomics of acute coronary syndromes

Acute coronary syndromes (ACS), such as unstable angina, acute myocardial infarction, and sudden cardiac death, are commonly associated with the presence of vulnerable plaques in coronary arteries. Rupture or erosion of vulnerable plaques results in the formation of luminal thrombi due to the physical contact between platelets and thrombogenic elements within the atherosclerotic lesions. Considering the socioeconomic burden of ACS, it is imperative that the scientific community achieves a clear understanding of the multifaceted pathophysiology of vulnerable atheroma to identify accurate prognostic biomarkers and therapeutic targets. The analytical power of modern proteomic technologies could facilitate our understanding of vulnerable plaques and lead to the discovery of novel therapeutic targets and diagnostic biomarkers.

Imaging of Inflamed and Vulnerable Plaque in Coronary Arteries with 18F-FDG PET/CT in Patients with Suppression of Myocardial Uptake Using a Low-Carbohydrate, High-Fat Preparation

PET/CT imaging with (18)F-FDG has been used to detect inflammation in carotid and aortic plaque; its use in detecting coronary plaque has been limited by avid (18)F-FDG uptake by the myocardium. We investigated whether (18)F-FDG PET/CT could be used to image inflammation in coronary arteries as a potential noninvasive method to detect vulnerable plaque. We retrospectively studied 32 patients treated for malignancy who underwent (18)F-FDG PET/CT and concomitant cardiac catheterization. As part of the recently described protocol, all patients were instructed to eat a low-carbohydrate, high-fat meal the night before and drink a vegetable oil drink the morning of the study. We reviewed the patients' baseline characteristics and their (18)F-FDG PET/CT scans for adequacy of myocardial uptake suppression and correlated the presence of angiographically apparent plaque with (18)F-FDG uptake in the major coronary arteries. Two independent observers assessed the angiographic images and (18)F-FDG PET scans. A total of 95% of patients had 2 or more coronary disease risk factors, and 25% had unstable symptoms; 30% of index catheterizations resulted in intervention. In 20 of 32 patients (63%), myocardial suppression was good (12) or adequate (8). Inadequate suppression was due to self-reported dietary nonadherence. Patients with good, adequate, and poor suppression had maximal myocardial standardized uptake values of 2.8 +/- 0.7, 5.0 +/- 1.3, and 17.0 +/- 9.7, respectively. We identified (18)F-FDG uptake in 15 patients in 1 or more coronary segments. A trend to significance in correlation between presence of angiographic disease and signal in the vessel was observed (P = 0.07; 80 vessels examined). A total of 7 patients with significant coronary artery disease had aortic (18)F-FDG uptake. In this retrospective study, we demonstrated the potential use of (18)F-FDG PET in imaging of inflammation in coronary arteries. The potential of (18)F-FDG PET is also being investigated in a prospective study.

Imaging of vulnerable coronary artery plaques

Advances in the identification of vulnerable plaque can be an important step in preventing myocardial infarction and sudden cardiac death. The recognition that non-flow-limiting plaques often produce cardiac events has led to the development of invasive and non-invasive methods to identify such plaques prospectively. This review will present the use of noninvasive imaging modalities for identifying vulnerable plaque such as computed tomography and magnetic resonance imaging. We will also review the different invasive modalities such as intravascular magnetic resonance imaging, intravascular ultrasound, coronary angioscopy, coronary thermography, optical coherence tomography, near-infrared spectroscopy, and palpography.